DMCA overrides the old court cases in this area, but (perhaps surprisingly to some) DMCA does not make it illegal to make personal copies of DVDs for your own use (in other words, it's okay as long as it's a legitimate fair use and not Internet-style fantasy fair use). It does, however, make it illegal for most people to sell and distribute devices or software that can do the job.
Basically, DMCA breaks DRM into two flavors, access control and copy control. Access control is the type of DRM that makes sure that you have a license to play a work -- software keys and the iTunes password protection are examples of access controls. Copy control is just that, a measure that prevents a medium from being copied -- The SCMS built into DAT and Minidisc players, and the CSS encoded into most commercial DVDs, are copy controls.
DMCA makes it illegal to develop or distribute something that circumvents either kind of DRM, with certain narrow restrictions for researchers, libraries and so on.
DMCA makes it illegal to circumvent an access control, with a very few narrow exceptions.
DMCA does not make it illegal to use a tool that circumvents a copy control, except that all the other restrictions built into older copyright law still apply. As above, (almost) no one is allowed to provide you with those tools.
For there to be penalties, DMCA requires that circumvention devices be created or used "willfully and for purposes of commercial advantage or private financial gain". That's probably the main reason why ripping tools are still so easy to obtain, the barrier is fairly high before it can really be enforced.
(I know what someone's going to inevitably ask: so why was DVD Jon arrested? He was still living in Norway at the time, and was dragged through court under Norwegian law. US DMCA stuff had nothing to do with him.)